In each of the following cases, is anyone required to register with HM Revenue and Customs? If so, who? 

(a) Lorna is a sole trader, making taxable supplies of £100,000 per annum. 

(b) Mike owns two distinct businesses. One has a taxable turnover of £40,000 per annum and the other has a taxable turnover of £50,000 per annum. 

(c) Pat and Phil are in partnership. Their taxable turnover is £60,000 per annum. Phil also owns another business with a taxable turnover of £45,000 per annum. 

(d) JSmiCo Ltd has a taxable turnover of £250,000 per annum. The company's shares are owned entirely by John Smith and his wife.